1. Field of the Invention
This invention relates generally to telecommunications, and, more particularly, to wireless communications.
2. Description of the Related Art
In the field of wireless telecommunications, such as cellular telephony, a typical system 100, as shown in FIG. 1, includes a plurality of base stations 130 (e.g., Node Bs) distributed within an area to be serviced by the system. Various Access Terminals 120 (ATs, also known as User Equipment (UE), mobile devices, and the like) within the area may then access the system and, thus, other interconnected telecommunications systems, such as a publicly switched telephone system (PSTN) 160 and a Data network 125, via one or more of the base stations 130. Typically, an AT 120 maintains communications with the system 100 as it passes through an area by communicating with one and then another base station 130, as the AT 120 moves. The AT 120 may communicate with the closest base station 130, the base station 130 with the strongest signal, the base station 130 with a capacity sufficient to accept communications, etc. The base stations 130, in turn, communicate with a Radio Network Controller (RNC) 138, which communicates with a core network 165. Each RNC 138 is capable of supporting a plurality of base stations 130.
In systems employing Universal Mobile Telephone System (UMTS) Long Term Evolution (LTE), communications are accomplished from the AT 120 to the base station 130 (i.e., the up-link (uplink)) using a packet switching system to increase system bandwidth utilization. However, scheduling of communications in the uplink has typically employed schemes, such as Hybrid Automatic Repeat reQuest (HARQ), that rely on feedback and control information from the opposite direction (e.g., down-link) to optimize performance. A substantial portion of the feedback information is characterized by its time sensitive nature and small packet size. The timing of data arrival in such a bi-direction interactive system presents a foreseeable challenge in the system design of uplink on-demand type scheduling schemes.
Multiplexing schemes for the feedback and control information (e.g., uplink pilot, data, and data associated L1/L2 control signaling) have been specified in section 9.1.1.2.3 of TR 25.814, Physical Layer Aspects for Evolved UTRA, 3GPP. The multiplexing schemes are designed to operate in the active mode in a Radio Resource Control (RRC) Connected state/LTE Active mode. Most technologies and access control studies focus on the active mode, which has a relatively long data transmission period. Multiplexing and control schemes that may be used during the idle and transient periods are not fully addressed in the technical report.
However, the general guideline in a packet type system is to shut down the connectivity when the idle period is long, so as to conserve power and resources. Once the connectivity is shut down, however, the AT 120 must re-request the connection after the idle period ends. However, the process used for re-requesting the connection is complicated and relative low in efficiency.